1. Field of the Invention
The invention is related to the field of IMS networks and, in particular, to the delivery of text messages to wireline phones through caller ID functionalities.
2. Statement of the Problem
One type of communication network gaining popularity is an IP Multimedia Subsystem (IMS) network. As set forth in the 3rd Generation Partnership Project (3GPP), IMS provides a common core network having a network architecture that allows for various types of access networks. The access network between a communication device and the IMS network may be a cellular network (e.g., CDMA or GSM), a WLAN (e.g., WiFi or WiMAX), an Ethernet network, or another type of wireless or wireline access network. The IMS architecture is initially defined by the 3GPP to provide multimedia services to communication devices over an Internet Protocol (IP) network, as IP networks have become the most cost savings bearer network to transmit video, voice, and data. Service providers are accepting this architecture in next generation network evolution.
Before user equipment (UE) of an IMS subscriber receives service from the IMS network, the UE attempts to register with the IMS network. To register according to 3GPP standards, the UE transmits a register request message, such as a SIP REGISTER, to a Serving-Call Session Control Function (S-CSCF) in the IMS network. Responsive to the register request message, the S-CSCF generates an authentication request message, such as a Diameter Multimedia Authentication Request (MAR), and transmits the authentication request message to a Home Subscriber Server (HSS). The HSS then authenticates the UE, such as through the AKA authentication method. If the UE is authenticated, then the S-CSCF generates a service profile request message, such as a Diameter Server Assignment Request (SAR), and transmits the service profile request message to the HSS. Responsive to the service profile request message, the HSS identifies the service profile for the user of the UE. The HSS then transmits a response message, such as a Diameter Server Assignment Answer (SAA), to the S-CSCF that includes the service profile for the user of the UE. The S-CSCF then transmits a register response message, such as a SIP 200 OK that includes information that the UE may use to communicate with the IMS network.
After registration is finished, the UE is able to exchange communications with the IMS network. One popular type of communication is text messaging. Text messaging refers to the interchange of short text message (i.e., typically 160 characters or less) between telephone devices. One type of text messaging is referred to as Short Message Service (SMS). IMS networks, and other types of communication networks, include Short Message Service Centers (SMSC) that manage the interchange of text messages.
To send a text message, a sending party enters text into a UE that is text-enabled, and also enters a phone number or address for the intended recipient of the text message. When the text message is completed, the UE sends the text message to the IMS network. An S-CSCF that is serving the sending party receives the text message and forwards the text message to the SMSC. The SMSC provides a store-and-forward mechanism where the SMSC temporarily stores the text message, and forwards the text message to the S-CSCF serving the recipient of the text message.
Some UE's that register with IMS networks are capable of handling text messages (i.e., they are text-enabled). The text messages are appended to a predefined header of signaling messages, which is how the text messages are sent through the IMS network from one UE to another UE. For example, a text message may be appended to a Content-Length header of a SIP MESSAGE. In order to “handle” text messages, the UE has an application that is operable to receive the signaling message, and process the signaling message to identify the appended text message from the predefined header of the signaling message. The application is further operable to provide a user interface for text messages, and to display the text message through the user interface. The application also allows a user to generate a text message, append the generated text message to the predefined header of a signaling message, and send the signaling message to the IMS network.
One problem encountered by service providers operating IMS networks is that some of the wireline phones (i.e., wireline UE's) that register with the IMS network are not capable of handling text messages. For instance, some VoIP phones are SIP-enabled and are capable of registering with the IMS network, but are not capable of receiving, displaying, or sending text messages. Text messages that are intended for these types of wireline phones unfortunately do not reach their destination.